It reminds me an effective way to learn a second language when you are in another country: find a "conversation partner", meet in a cafe and speak half an hour in your language and half hour in your partner's language. Best way to get into other language, and productive for both. Can't fail for learning other kind of stuff too. Also, it can be optimized with a good matching-partner system (by knowledge, level of expertise, area of application, etc) in order to make both people satisfied.